The genus Aeromonas comprises more than 60 recognized species that include many important fish pathogens such as the causative agents of furunculosis and motile Aeromonas septicemia (MAS). Although MAS is typically considered a secondary infection, a new virulent A. hydrophila (vAh) strain has been causing devastating losses to the catfish industry in Alabama since 2009. The objective of this study was to characterize the spatiotemporal distribution of Aeromonas sp. and, specifically, vAh in a commercial catfish farm in western Alabama. We sampled biofilm, sediment, and water from three ponds during four consecutive months during the growing season. Total aerobic counts were between 8.8 × 105 and 1.5 × 106 CFU/mL but were significantly higher in biofilm and sediment than in water throughout the sampling period. Total Aeromonas counts in water samples significantly increased in all three ponds after the month of August and ranged from 7.8 × 103 to 4.9 × 104 CFU/mL. A similar trend was observed in biofilm and sediment samples for which total Aeromonas counts increased in samples taken in late summer to early fall. Over time, the concentration of Aeromonas in water samples decreased by one order of magnitude, while there was a significant increase in sediments as temperature dropped. The virulent vAh was detected in 35.4% of biofilm samples and 22.9% of sediment samples, suggesting that both environments serve as the major reservoir for this pathogen. Future monitoring efforts should focus on targeting sediment and biofilms since samples of these appear to naturally enrich for the presence of vAh and other Aeromonas species.

中文翻译：

---

生物膜和沉积物是鲶鱼生产池塘中有毒嗜水气单胞菌 (vA h) 的主要储存库

气单胞菌属包括 60 多个公认的物种，其中包括许多重要的鱼类病原体，例如疖病和活动性气单胞菌败血症 (MAS) 的病原体。尽管 MAS 通常被认为是继发性感染，但自 2009 年以来，一种新的毒力嗜水链球菌 (vAh) 菌株对阿拉巴马州的鲶鱼产业造成了毁灭性的损失。本研究的目的是表征气单胞菌的时空分布。尤其是阿拉巴马州西部一个商业鲶鱼养殖场的 vAh。我们在生长季节连续四个月从三个池塘中取样生物膜、沉积物和水。总有氧计数在 8.8 × 105 和 1.5 × 106 CFU/mL 之间，但在整个采样期间，生物膜和沉积物中的生物膜和沉积物明显高于水中。8 月之后，所有三个池塘中水样中的气单胞菌总数显着增加，范围为 7.8 × 103 至 4.9 × 104 CFU/mL。在生物膜和沉积物样品中观察到类似的趋势，在夏末至初秋采集的样品中，气单胞菌总数增加。随着时间的推移，水样中气单胞菌的浓度下降了一个数量级，而随着温度的下降，沉积物的浓度显着增加。在 35.4% 的生物膜样本和 22.9% 的沉积物样本中检测到有毒的 vAh，表明这两种环境都是这种病原体的主要储存库。未来的监测工作应侧重于针对沉积物和生物膜，因为这些样品似乎自然富集 vAh 和其他气单胞菌物种的存在。